Post-Miocene rifting and diapirism in the northern Red Sea

Rifts and diapirs are the dominant structures in the bathyal zone of the northern Red Sea, where commonly the diapirs ascend along normal faults associated with the rifts. In this manner, the diapirs form elongated features sometimes exceeding lengths of 30 km and widths of 4 km. They also penetrate a sedimentary sequence about 1000 m thickness or less, thicknesses generally considered to be barely adequate for the gravity conversion required to initiate diapiric motion. We suggest that development of diapirs under these minimal overburden conditions was made possible by the high thermal gradients in the area, resulting from the underlying attenuated continental crust and ascending mantle, that prevail in the rift system of the northern Red Sea. Diapiric evolution was also dependent on the extensional tectonic regime, with its numerous normal faults forming weaknesses along which the diapirs could move upwards.